Saving a Model Generated File in SharePoint - New Copilot Studio

The file storage behavior you're experiencing is a documented platform limitation, not a configuration issue.

In the new Copilot Studio experience, files created by the agent during a conversation are stored ephemerally (10 MB max, 28-day retention) and only surfaced as a download card.

There is no native mechanism to route those bytes to SharePoint automatically.

The only documented path involving SharePoint file creation (Document Output Content Bytes => SharePoint via cloud flow) is limited to the Copilot Studio prompt builder, which runs on GPT models via Azure OpenAI.

Not on Claude...

So restructuring around that approach means giving up Claude, which you've already ruled out for formatting quality reasons.

At this time, there is no documented native solution for: Claude-generated file + new experience + automatic SharePoint save without human interaction.

One architectural option worth exploring: use Claude to collect and structure all data during the conversation, then call a cloud flow tool that passes that structured content to a GPT-based prompt with a Word template, which generates the file and saves it to SharePoint via the Content Bytes.

The trade-off is that document formatting is then governed by the Word template and GPT, not Claude's free-form output.

Hope this helps